The present invention relates generally to the transmission of information across the Internet, and more specifically to methods, systems, and apparatus for rapid, real-time transmission of information across the Internet and within networks and networked systems.
Many Internet based applications require real-time transmission and exchange of data for effective implementation. By way of example, H.323 Internet video conferencing provides rapid, real time data exchange to present video and audio data for participants in local and remote settings. Typically, to realize the benefits of necessary real-time data exchange, data is transmitted over unreliable User Datagram Protocol/Internet Protocol (UDP/IP, or simply UDP). The advantage of using the unreliable UDP over the reliable Transmission Control Protocol (TCP, also TCP/IP) is primarily an advantage of speed. UDP has less overhead since it does not transmit packet acknowledgement, packet verification, packet re-transmission requests, etc. In real time media transmission and play-back, such transmissions and verification processes negatively impact the system performance.
TCP serves as essentially the standard for most Internet data transmission. TCP maintains the highest degree of reliability by ensuring all data is received, received in the correct order, and that the data received is accurate and consistent with the data that was transmitted. In many applications, such reliability is paramount for effective data transmission. The highest degree of reliability, however, is not necessary for applications such as H.323 Internet video conferencing, where speed is paramount. Most video-conferencing applications can easily compensate for occasionally missed audio data, which is generally imperceptible, and similarly, occasionally missed or garbled video data is generally easily tolerated and of little hindrance to video conferencing sessions.
FIG. 1 is a simplified schematic diagram of computers exchanging information without a firewall. Computers 100 and 102 establish a TCP connection after exchanging handshake signals 104. With reference to videoconferencing standards, e.g., H.323, multiple UDP port numbers are established for communication of the audio and video data. At least 4 UDP ports, 108-1 through 108-4 and 110-1 and 110-4, for each of computers 100 and 102, respectively, are opened for the audio and video control/data signals. Typically more than four ports are opened for each of computers 100 and 102 as illustrated by ports 108n and 110n. 
However, many office and home networks are protected within firewall environments. As is generally known, firewalls are designed to keep out unwanted Internet Protocol (IP) traffic from a network by restricting the number of ports being unblocked. This creates a problem for videoconferencing standards as the videoconferencing standards require a large number of TCP and UDP ports to be unblocked. FIG. 2 is a simplified schematic diagram of two computers communicating through a firewall. As illustrated in FIG. 2, computer 100 is behind firewall 112 and computer 102 communicates with the firewall over network 114. As mentioned above, firewall 112 does not allow the multiple port opening required by a UDP connection. Furthermore, since firewall 112 limits the ports being unblocked, the firewall will not recognize any UDP ports, such as UDP port numbers 1024-65,538, all of which may be used for a videoconference application.
When rapid, real-time transmission is desired, a firewall can and often does limit or prevent desired video conferencing capability. If a particular firewall blocks or denies all incoming Internet traffic except TCP/IP, then videoconferencing or any other data exchange, must be conducted using highly reliable, but much slower, TCP/IP, or some work-around must be established to conduct UDP data transmission and exchange. One attempt to address this shortcoming is the use of a TCP/IP connection for the data. However, the TCP connection results in poor quality video due to transmissions of acknowledgement, verification, and requests for the retransmission of missed packets, i.e., the reliability characteristics of the TCP connection.
In view of the foregoing, what is needed is a method and system of communicating videoconference data through existing firewalls with minimal impact on the audio/video data transmission, or on the system administrator's burdens of administration.